All major ISPs in the UK are resellers of the same fibre infrastructure, run by OpenReach[0], a subsidiary of BT (formerly the national telco, now one of the larger ISPs).
OpenReach has to provide equal access to other ISPs by law, so the playing field between them is very even.
The only major outlier is Virgin Media, who own the cable (as in cable TV) network covering some built-up bits of the county; their fibre network is entirely separate.
OpenReach has to provide equal access to other ISPs by law, so the playing field between them is very even.
The only major outlier is Virgin Media, who own the cable (as in cable TV) network covering some built-up bits of the county; their fibre network is entirely separate.
[0]https://www.openreach.co.uk/